The invention relates-to a device for conveying flat objects, held vertically, at high speed along one of their long dimensions and one after another, between processing equipment items in an installation, and in particular for conveying mail envelopes of varying size in a postal sorting installation.
The conveying of flat objects, one after another, between two items of processing equipment, is currently achieved using an endless belt on which the flat objects are placed in succession. However, such conveying is unsatisfactory when the objects have to be presented vertically, for example for direct reading at a sorting station, and an arrangement for changing the orientation of the objects has then to be provided.
Another known solution for conveying flat objects one after another is obtained by using a motorized corridor between the processing equipment items that are to be connected. This corridor comprises a base belt on which the flat objects are placed edge-on, because of their weight, and two lateral belts between which the flat objects pass in succession in order to be conveyed. The mechanical arrangement needed to operate a motorized corridor has the drawback of being relatively complicated and it is known that this solution is not very appropriate when soft objects are to be found among the succession of flat objects, of different sizes, conveyed at high speed between processing equipment items.
An alternative version of the solution for conveying flat objects one after another mentioned hereinabove envisages holding the flat objects by gripping them between a broad lateral belt, which serves as a reference, against which the flat objects are pressed, and a narrow lateral press belt. For this, the press belt is pressed against the broad reference belt by mobile rotary pulleys spread out along that part of the
conveying path which is followed by both of the belts between two processing equipment items. Here again, the mechanical arrangement needed has the drawback of being relatively complicated and the solution adopted is suited only to a small range of differences in thickness between successive flat objects.
In order to overcome these drawbacks, the invention therefore proposes a device for conveying flat objects, held vertically, at high speed in a movement along one of their long dimensions and one after another, between processing equipment items, and in particular for conveying mail envelopes of varying size in a postal sorting installation.
According to one feature of the invention, the device comprises:
a stationary baseplate extending from one equipment item to another to allow the envelopes, resting on their edge, to slide;
a broad motorized endless reference belt stretched over a set of vertical pulleys mounted on fixed axles and extending, in particular, above the baseplate, along the edge of which this belt extends along the conveying path between equipment items, so as to provide lateral support for the envelopes in a vertical position;
a motorized endless press belt mounted on a set of vertical pulleys with fixed axles in such a way that it can be pressed against the reference belt along the conveying path between equipment items followed by this reference belt, so as to grip the envelopes introduced between the latter belt and itself at one end of the conveying path followed;
a series of free and elastically deformable wheels, mounted on fixed vertical axles along the conveying path between equipment items, so as to come to bear against the press belt in the zone where the latter presses against the reference belt, so as, by elastic deformation, to grip all the envelopes conveyed appropriately in spite of the differences in thickness there may be between these envelopes.
According to one feature of the invention, the wheels are longitudinally offset with respect to the pulleys of the set carrying the reference belt along the conveying path between equipment items.
According to one feature of the invention, the spacing between wheels and between pulleys is shorter than the intended spacing between two objects being conveyed one after the other.
According to one feature of the invention, at least one fixed guide is mounted so that it is parallel, along the conveying path followed by the belts between the equipment items, so as to provide support to the upper parts of the envelopes being conveyed at least on that side on which these envelopes are gripped by the press belt.
According to one feature of an alternative form of the invention, several guides are mounted in parallel at different heights along the conveying path followed by the belts between the equipment items, so as to provide support to the upper parts of the envelopes being conveyed, according to the height of these envelopes, and at least on that side where the press belt grips them.